Page "Qin Shi Huang" Paragraph 9

Zhao Zheng was born in the first month of the year Zhengyue ( 正月 ) thus he received the character Zheng ( 正 ) as given name.

According to the footnote of the " The lunar calender of Qin and Chu " (《 秦楚之际月表 》) from the Index of the Records of the Grand Historian (《 史记索隐 》), the first month Zhengyue, " due to the taboo of the First Emperor's given name Zheng, was reformed as Duanyue ( 端月 ).